Fitting replacement pads

[Nigel Champion]

I'm replacing the pads in a Lachenal 48-key English concertina but aligning the pads is driving me crazy! 

 

Despite the embossed circles around the holes on this concertina being poorly-formed and in many instances not concentric, I've managed to get the pads sitting centrally over the holes.  However, when I try to position a lever and its little leather bead on the pad, the tendency of the lever to flop sideways without the support of the bushed hole in the fretwork throws everything out-of-whack!

 

I tried making cardboard jigs to hold each row of keys vertical but with limited success.  I can see no way around the problem other than making a complete bushing board as used on metal ends.  Does this mean it's time to replace the action plate due to excess wear in its holes?  I've searched David Elliott's book and Concertina.Net for guidance on this all to no avail.  Am I missing some crucial step?

 

Any help appreciated.

All the Best

Nigel

[Mike Acott]

The problem is likely to be caused by the springs exerting a sideways  pressure on the levers,new properly fitted springs will cure the problem.

Mike

[d.elliott]

I agree with Mike, the other caused can be if an arm is cranked or bent to pass around other keys etc . this can cause the arm/ pivot post 'window' to wear which allows the the arm to twist and operate on an angle.

[Frank Edgley]

Carefully trace the holes in the bushing board onto a piece of 1/8 inch plywood.. Drill them out using a lipped brad point drill just slightly larger diameter than the buttons. For example 1/4 inch buttons need 17/64ths of an inch hole. Doesn't have to be fancy, just accurate. Outside shape can be a rectangle or whatever, but not too large as to interfere with you work..This should hold the buttons up as if the end is on. Then when the end is replaced, it should line up.

[Nigel Champion]

Thanks very much, Frank. 

 

I was hoping there might be a way to avoid this effort as it needs to be done for both ends {sigh}. 

 

However, old concertinas are deserving of such care.  I'll follow your excellent guidance but may add a couple of "wings" to reach the two screw holes securing the fretwork cover.

 

All the Best

Nigel

[RWL]

I have not done this, but I would think that if you're careful, you could use the existing end and its pad board as your template and drill directly into the new wood template.  Just don't drill the existing button holes larger or tear out the felt.  Maybe use a drill that is a little under size, but can easily be centered visually. Wire size drills (number drills) would be your friend here because they change in increments of only a few thousandths of an inch.  I'm watching your thread with interest because I'm contemplating repadding a couple of instruments and may face the same challenge.

[Rod Pearce]

Nigel

 

It is likely that the new pads you fit will be thicker that the ones you remove, which will have been compressed over the years. This will affect the height of the buttons, which you would need to adjust by bending the lever arms. From memory this is described in Dave's book.

[RogerT]

Getting the pads to stay put and centred on the holes can be a pain. I put a tiny mark on centre of the pad so I can check the alignment from the other side. 

[Chris Ghent]

On 2/18/2022 at 12:34 AM, RogerT said:

Getting the pads to stay put and centred on the holes can be a pain. I put a tiny mark on centre of the pad so I can check the alignment from the other side. 

This is an excellent method. It also aids in finding pads which move sideways a little when the end is put on because the lever is not perfectly above the button spigot hole. 

Edited February 21, 2022 by Chris Ghent
Edited for extra thought.

[Nigel Champion]

Thanks Roger.  I was using this centred-spot idea to measure my positioning after reassembling the action box but, until Frank's technique, I felt I was going round in circles!

 

Many thanks to all

Nigel

[RogerT]

I mostly position the pads by lifting the end on and off, but in desperation one time I used a variation on Franks method and made an end hole jig from a thick bit of card and using a hole punch.